Hurricane Ike has swept through the southern U.S. state of Texas, flooding homes and businesses, knocking out electricity to hundreds of thousands, and cutting a path of destruction all the way up to Houston - the nation's fourth-largest city.

More than three million people are reported to be without power from Houston to Galveston on the Texas Gulf of Mexico coast. Officials say it may take weeks to completely restore electricity.

Authorities are beginning search and rescue operations in hard-hit areas. The massive storm had prevented them from responding to thousands of emergency calls overnight into this Saturday morning.

They said they are particularly concerned about the safety of thousands of people who defied evacuation orders in Galveston and the surrounding area, where the storm first made landfall.

Large sections of Galveston were left underwater from massive flooding. Winds of more than 175 kilometers per hour also knocked out power lines, and spawned fires that officials had to let burn.

U.S. President George Bush called Hurricane Ike a "huge storm" that is causing great damage. In a statement at the White House this morning, he said he is sending Homeland Security chief Michael Chertoff to the Gulf Coast region to assist officials with the recovery effort.

Mr. Bush also announced that his administration had extended environmental waivers on imported gasoline, in order to offset the disruption of U.S. fuel facilities in the Gulf of Mexico.

Gasoline prices have gone up across the country because of concerns about possible supply shortages.

Hurricane Ike is still bringing heavy wind and rains to the Houston area, but is expected to weaken as it continues moving farther inland to the north and east.